sound proofing windows?

[Freudian Slip]

I have a live space that I need to do some sound proofing on. The walls are built in leaving a large sill on the windows. The current windows are regular vinal dual pane windows. I originally planned to build caps out of wood and drywall that could be gasketed to the inner wall. The plan is to cutt the drywall in the sill to decouple the inner wall from the outter wall around the windows.

Well since I have finished the space I have grown fond of the natural light coning into the room and the view isn't bad either. So my question is. What do you think the best treatment would be that would at least leave me some natural light. I have considered a thick tilted lexan or plexiglass inner window, Glass blocks and also the laminated "quiet" glass.

Any ideas on what might be best or other options, or is nothing going to come close to a couple sheets of dywall w/green glue screwed to some plywood?


PS. so you know the inner wall is 1 sheet of 5/8 drywall with insulation behind. The outter wall is 3 sheets of 1/2 inch drywall with green glue. The exterior wall is plywood & hardey plank. The plan is to vent the ext. wall to avoid the three leaf thing.


Thanks

F.S.

 

[bpape]

From a pure soundproofing standpoint, you simply need mass. The problem with doing Lexan or anything else that's stiff is that you'll end up with an empty cavity between it and the existing window that will function like a big drum.

Now, you can use clear limp mass vinyl in a couple of layers that will give you decent mass but not have the resonant issues as long as it's left a bit on the loose side (not stretched tight).

While it's not the clearest thing in the world as far as seeing outside, it will at least still allow some light in.

Bryan

 

[Rod Gervais]

I would probably opt for a thick piece of laminated glass - thickness depending on the window size.

I wish you had spoken to us as to your plans before building - even with venting of the outer wall - you still have a 3 leaf system - that's a shame.

Rod

 

[Ted White]

Rod, can I ask what the relation of glass thickness is to window size? Bigger window requires thicker glass due to bigger hole = bigger potential leak? Lower frequencies more problematic?

Thanks for the assist.

 

[Freudian Slip]

I would probably opt for a thick piece of laminated glass - thickness depending on the window size.

I wish you had spoken to us as to your plans before building - even with venting of the outer wall - you still have a 3 leaf system - that's a shame.

Rod

Why would I have a tree leaf system if the ext. wall is vented. Are you saying that venting will not solve the issue?

I could vent pretty good between the inner and mid wall with pretty strong flow by removing the fire blocking at the top of the wall (something the inspector said I had to do, or by placing larger vents on the inside wall.
Is this any better?

I wish I had spoaken to you too. I was on a deadline and I had to stay ahead of the contractors sooooo, I spoak to the building inspector and got the ok to put the sheet rock on the inside of the outter wall. The rest of the room was drywalled by a DW company and I did not want to pay them for installing multiple layerd on the inside wall.

Help me if ya can

F.S.

 

[Rod Gervais]

Why would I have a tree leaf system if the ext. wall is vented. Are you saying that venting will not solve the issue?

I could vent pretty good between the inner and mid wall with pretty strong flow by removing the fire blocking at the top of the wall (something the inspector said I had to do, or by placing larger vents on the inside wall.
Is this any better?

Perhaps a little - but it still creates a back pressure that will affect the TL values of the wall.

Think about it - you have sound pressure build up against a wall inside a room with no wall in front of it. You have sound pressure build up in a Helmholtz Trap even if you use 1x4 boards spaced with 4" air spaces between them - what kind of pressure relief from sound pressure do you think your little vents are going to be? Or the loss of the fire blocking at the top of the wall (which I would have to see - Fire blocking is required to contain the flow of fire from one compartment into another - the official requiring you to remove it boggles my mind - take some pictures so I can see what he's talking about.)

I wish I had spoaken to you too. I was on a deadline and I had to stay ahead of the contractors sooooo, I spoak to the building inspector and got the ok to put the sheet rock on the inside of the outter wall. The rest of the room was drywalled by a DW company and I did not want to pay them for installing multiple layerd on the inside wall.

Well the building official doesn't know squat about acoustics - and from his perspective it doesn't hurt anything from a construction point of view having drywall there - so his OKing that doesn't surprise me - BUT - you take the blame here - being in such a rush as to do it wrong? It isn't llike this idea popped into your head and then had to be put into play in a five minute period - you could have taken the days before you hired the drywall contractor or began construction to ask the question.

Help me if ya can

There isn't anything I can do to help - and the window in that location won't do much of anything because the inner most wall is one of the weak links in your system - installing anything greater than your single layer of drywall will gain you nothing.

I'm not a magician - so I am afraid I can't help you.

Rod

 

[Rod Gervais]

Rod, can I ask what the relation of glass thickness is to window size? Bigger window requires thicker glass due to bigger hole = bigger potential leak? Lower frequencies more problematic?

Thanks for the assist.

The thicker the glass the stiffer the glass - and within reason - this means greater LF TL values - HOWEVER - this is tempered by the mass you're installing for the wall itself - picture (if you will) that you install only a single layer of 5/8" drywall for the wall surface - then installing a piece of glass with mass equivilent to 3 sheets of 5/8" drywall is not going to gain you anything.

Huge windows can vibrate quite easily though with thin glass pieces - and the accompanying hum can be noticable. Low frequencies will pass through them like a hot knife through butter.

And plexiglass is a waste of time and moneyu - not enough mass to make it worth anything.(Never mnd the fact tha tit scratches as easy as all get out).

Rod

 

[Freudian Slip]

Perhaps a little - but it still creates a back pressure that will affect the TL values of the wall.

Think about it - you have sound pressure build up against a wall inside a room with no wall in front of it. You have sound pressure build up in a Helmholtz Trap even if you use 1x4 boards spaced with 4" air spaces between them - what kind of pressure relief from sound pressure do you think your little vents are going to be? Or the loss of the fire blocking at the top of the wall (which I would have to see - Fire blocking is required to contain the flow of fire from one compartment into another - the official requiring you to remove it boggles my mind - take some pictures so I can see what he's talking about.)



Well the building official doesn't know squat about acoustics - and from his perspective it doesn't hurt anything from a construction point of view having drywall there - so his OKing that doesn't surprise me - BUT - you take the blame here - being in such a rush as to do it wrong? It isn't llike this idea popped into your head and then had to be put into play in a five minute period - you could have taken the days before you hired the drywall contractor or began construction to ask the question.



There isn't anything I can do to help - and the window in that location won't do much of anything because the inner most wall is one of the weak links in your system - installing anything greater than your single layer of drywall will gain you nothing.

I'm not a magician - so I am afraid I can't help you.

Rod

On the fire blocking. The inspecter required it. I said I could remove it allowing the space between the first and second wall to vent into te cavity above the ceiling, which would not be a huge issue for me because the inside of the outer wall continues up with the 3 layers on it.

I was not expecting the inspecter to know anything about it.

I had about a week to do something before the framing was up after I found out we were going to get the house. Then I had to conform to the rehab loan and budget. So ya it was not an ideal start. I can take all the time in the world on the cr and iso booths. only problem there is this inspector telling me I have to block every chase. I am going to see if I can use foil backed insulation or something for that so I don't have to couple the walls together.

Fire blocking and window sills is the only thing coupleing the live space to the outside walls. Now that inspection is done I am free to do what I want within reason.

Well thanks anyway. I'll do some looking around. If I have to take drastic measures I will. I'm going to cap the windows for now with a couple laters of 5/8's and see what I have got in the low end area and go from there. No telling what I will end up with. there are some large places it's two leaf with one of the leafs being about 14" of cement. Bass and drums will be placed accordingly.


F.S.

 

[Freudian Slip]

The thicker the glass the stiffer the glass - and within reason - this means greater LF TL values - HOWEVER - this is tempered by the mass you're installing for the wall itself - picture (if you will) that you install only a single layer of 5/8" drywall for the wall surface - then installing a piece of glass with mass equivilent to 3 sheets of 5/8" drywall is not going to gain you anything.

Huge windows can vibrate quite easily though with thin glass pieces - and the accompanying hum can be noticable. Low frequencies will pass through them like a hot knife through butter.

And plexiglass is a waste of time and moneyu - not enough mass to make it worth anything.(Never mnd the fact tha tit scratches as easy as all get out).

Rod

I'll check with the local shop and see if they can get laminated glass. If they can I will mount it inline with the middle leaf. I have an that might work for venting the inner wall with some 2'x4' vents.

We'll see.

F.S.

 

[Rod Gervais]

On the fire blocking. The inspecter required it. I said I could remove it allowing the space between the first and second wall to vent into te cavity above the ceiling, which would not be a huge issue for me because the inside of the outer wall continues up with the 3 layers on it.

You're creating a deadly situation removing the fire b-locking - it's designed to stop fire from being able to enter the space between the wall cavity and the ceiling above - which acts like a chimney if ever there was a fire........ allowing it to engulf the space surrounding the room.

If you own and there was ever a fire - your insurance company will probably abandon you after verifying with the building inspectors records that there was fire blocking inspected - which then dissapeared......

If you rent an apartment - you would be lible for any and all damages - and possibly eligible for criminal charges as well.

This is a serious issue - and one which you should really ethink.

Again - had you asked - there are many methods of fireblocking (quite a few detailed in my book) that you can use with no decoupling of structure.

IWell thanks anyway. I'll do some looking around. If I have to take drastic measures I will. I'm going to cap the windows for now with a couple laters of 5/8's and see what I have got in the low end area and go from there. No telling what I will end up with. there are some large places it's two leaf with one of the leafs being about 14" of cement. Bass and drums will be placed accordingly.

Unfortunately you isolation is as good as your weak links in the system - so don't count on the concrete walls helping all that much......


I really do wish you luck - it's a pain when this crap happens.

Sincerely,

Rod

 

[Freudian Slip]

You're creating a deadly situation removing the fire b-locking - it's designed to stop fire from being able to enter the space between the wall cavity and the ceiling above - which acts like a chimney if ever there was a fire........ allowing it to engulf the space surrounding the room.

If you own and there was ever a fire - your insurance company will probably abandon you after verifying with the building inspectors records that there was fire blocking inspected - which then dissapeared......

If you rent an apartment - you would be lible for any and all damages - and possibly eligible for criminal charges as well.

This is a serious issue - and one which you should really ethink.

Again - had you asked - there are many methods of fireblocking (quite a few detailed in my book) that you can use with no decoupling of structure.




Unfortunately you isolation is as good as your weak links in the system - so don't count on the concrete walls helping all that much......


I really do wish you luck - it's a pain when this crap happens.

Sincerely,

Rod

Thanks Rod.

I'll do what I have to do now that the loan is satisfied. I'll leave the fire blocking or perhaps change it out, right now it's drywall and it's tying the walls together. Perhaps I will grab your book for some suggestions.

F.S.

 

[Rod Gervais]

I am not trying to sell you a book - provide me some details of what you have and I will provide some details for what you can do....... I don't need to make money off of the book with someone who is almost finished their construction. '

That is not what I have been trying to achieve here.

I apologize if that is how this came to look.

Sincerely,

Rod

 

[Freudian Slip]

I am not trying to sell you a book - provide me some details of what you have and I will provide some details for what you can do....... I don't need to make money off of the book with someone who is almost finished their construction. '

That is not what I have been trying to achieve here.

I apologize if that is how this came to look.

Sincerely,

Rod

Oh no, don't worry about it. I've got many books. this would only be one more And I still have a CR and a couple of ISO rooms to do.
Since ya offer though, The outer wall is a 2x6 wall with chip board and hardyplank (cement boad) on the ext. That wall is un-insulated and has 3 layers of 1/2 inch with green glue going all the way up (around 12 feet).

The inner wall is 2x4 construction, insulated with the paper against a layer of 5/8 sheet rock. The ceiling is dropped via hangers and the inner walls about 2 feet and has un-backed insulation. bwtween the inner wall studs and the outter wall sheetrock there is around a 2 to 3 inch air gap. The only coupling from the inner to the outer wall is drywall screwed to one wall only and sealed with 3 fire block calking at the top of the wall and every ten feet verticaly. I have the ability to mount a inner window to either the inner wall frame or the outer wall frame (sounds like outter wall may be the way to go).

Will it help me to tilt the glass at a pitch for the inner window, make it a different thickness of glass than the combined outer pains? What type of air gap should I leave between the inner and outter windows?

The window size is about 4.5ft x 3.5 ft.

I also have a blasted steel french door. The only thing I have thought of there is to actually screw some quiet rock flush to the door by first removing the window trim so the sheetrock will lay flat against the door. I was planning to cover the whole door not just the glass and then frame it in angle aluminum or something similar to keep the rock in one peice. I know I may have sag problems, but aside from heavey vinal curtains or a rolling cap I can think of nothing else and the sheet rock seems like the ugliest and most effective thing to do.

On the third leaf problem I could frame some oc703 without a backing board and remove 2"x4" sections of the inner 5/8 drywall from around the room where I could install these pannels. I would have to remove any backing on the insulation to prevent it from acting as a leaf. I don't know if the 703 would allow air to come through it well enough and I would not want a low end resonance projecting back into the room. I am also not shy about installing 3x10 (or larger if need be) around the top and bottom of the inner wall.


Also would blowing in more insulation harm or help the cause to any significant degree?

The rest of the rooms will be done by me and will have two leaf systems from the get go. For the most part my concern with those rooms is going to be room to room leakage from the CR & vocal booth to any other room. I will likely step it up a on the drywall thickness. Do you use back mounting gang boxes for outlets etc. to make life easier with a thick wall like that?

Just as a stupid question, what do you think has the higher stc, the chipboard with hardey plank on it, or the 5/8 sheet rock with r21 behind it.

Well you asked for it Take your time and I am sure I left out something you need.

Room is 600 sq feet with 10"3' ceiling on a cement slab.


Thanks

F.S.

 

[RICK FITZPATRICK]

Hello FS. Say, I haven't followed your construction for a while, so I didn't see how you detailed the leafs. But I'm a little confused.

The outer wall is a 2x6 wall with chip board and hardyplank (cement boad) on the ext. That wall is un-insulated and has 3 layers of 1/2 inch with green glue going all the way up (around 12 feet).

PS. so you know the inner wall is 1 sheet of 5/8 drywall with insulation behind. The outter wall is 3 sheets of 1/2 inch drywall with green glue. The exterior wall is plywood & hardey plank. The plan is to vent the ext. wall to avoid the three leaf thing.

Well since I have finished the space

So, if I understand this correctly, the PICTURE must be showing the single layer drywall interior "boundary wall"...

If that is the case, I REALLY don't understand. Why did you drywall the interior face of the exteriior framing with THREE layers of DW, and then build a "room within a room" with only ONE layer, and THEN...not only penetrated the whole thing with windows and a french door through the interior envelope, but tied the two envelopes togeather with drywall sills...?

FS, I don't get it. What I DO get is DRAGONS REFUSAL to allow more "stickys" on this forum that would illustrate these principles so people DON"T make these kind of choices from the getgo. After all, look at the "stickys" on the other forums here... Compared to this type stuff, either DRAGON doesn't get it or he plain doesn't give a shit. Pisses me off. Especially when I see this type of mistakes that could have been avoided had you had ACCESS to EASILY READ "stickys" that cover the basics in the first place. So be it. Anyway, I wasn't trying to add insult to injury here, but I see this kind of stuff all the time. EVEN, a sticky for RODS BOOK would help! AND, maybe, a link to the STANDARDS that Rod mentioned a few weeks ago. IF, they were available FREE!

The members here who constantly try to help are getting NO help from Dragon. Shame on him. No wonder its becoming a joke.
fitZ

 

[Freudian Slip]

Hello FS. Say, I haven't followed your construction for a while, so I didn't see how you detailed the leafs. But I'm a little confused.







So, if I understand this correctly, the PICTURE must be showing the single layer drywall interior "boundary wall"...

If that is the case, I REALLY don't understand. Why did you drywall the interior face of the exteriior framing with THREE layers of DW, and then build a "room within a room" with only ONE layer, and THEN...not only penetrated the whole thing with windows and a french door through the interior envelope, but tied the two envelopes togeather with drywall sills...?

FS, I don't get it. What I DO get is DRAGONS REFUSAL to allow more "stickys" on this forum that would illustrate these principles so people DON"T make these kind of choices from the getgo. After all, look at the "stickys" on the other forums here... Compared to this type stuff, either DRAGON doesn't get it or he plain doesn't give a shit. Pisses me off. Especially when I see this type of mistakes that could have been avoided had you had ACCESS to EASILY READ "stickys" that cover the basics in the first place. So be it. Anyway, I wasn't trying to add insult to injury here, but I see this kind of stuff all the time. EVEN, a sticky for RODS BOOK would help! AND, maybe, a link to the STANDARDS that Rod mentioned a few weeks ago. IF, they were available FREE!

The members here who constantly try to help are getting NO help from Dragon. Shame on him. No wonder its becoming a joke.
fitZ

Well Rick. This was a special situation. As I tried to explain without to much detail. This is a house that was forclosed on several years ago. we did not thik we would get it because we where out bid on our offer. When we did get it we bought it with a construction/rehab loan. The numbers on a rehab loan have to look real good to get one. So starting value and ending value have to be drasticaly different leaving you with tons of equity. We could barely budet finishing 600 sq ft of the basment at all, but had to for the numbers to work.
Anyway. I took money out of my own pocket and put up the dywall in the inside of the ext wall. The framers where coming to start and I had about 3 days to do anything. So I thew it up knowing it would be better than no extra dry wall. Because of the fact that the framing and drywalling was budgeted for typical construction it was all I could do at the time. I knew full well I would have issued to face when the time came to really get it ready for recording. The windows & doors still remaining is simply a finance descision that was made. Most of the money went into the upstairs and the plan is to pull money after the conversion of the loan to finish the studio area.

So you see I put up the drywall because it is all I could do and "if" the drywallers would even layer the inner walls I could not have aforded to pay them at the time. I simpley did not have the luxury of making a strictly studio based decission at the time and I felt a three leaf system with 1.5 inches of drywall and GG while not ideal was better than a single layer of drywall on a two leaf system. Jury is out in that, but I am not opposed to some farely dramatic changes. I figured I would be angling some walls and what not anyway.

As far as the drywall sills are concerned I was better off letting the non-english speaking drywallers do them normaly and plan to cut them later, which has been the plan all along.

So now I am stuck trying to get the best bang for my buck out of the situation I am in.
The fench doors and the windows will remain in a reversable state from anything I have to do to them because of the river view.

I may put in solid wood double doors and heavy curtains in place of the french doors. It's up in the air.


The upper two stories where all of the money went. It's just the way it had to be
It will get me the money to finish the basement right though

some before and afters. So you can see I've been busy

The info is there for those that want it. You guys are always around and people have but to google, but a sticky on the basics would be nice.

F.S.

 

[Freudian Slip]

A bit of a post I found regarding "heat mirror" glass.





"When considering windows, there are generally three options available for maximum possible sound attenuation.

First is laminated glass.
Second is a wider airspace between the lites.
Third is using two lites of different thickness in the IGU or Insulating Glass Unit.
Fourth would be a combination of all three.

Airport windows, for example, will generally have laminated glass on both sides of the IGU in an aluminum frame and with a "maximum" airspace between the lites. In an airport the primary concern is sound attenuation and energy efficiency is secondary. I mention this because the width of the airspace and the choice of window framing material affects both sound and energy efficiency.

Some folks will suggest triple pane glass for its sound deadening ability. And while triple pane is a slight improvement over standard double pane at lower frequencies due to the additional density of the extra lite, overall there is no difference in STC rating between triple and double pane provided that the overall airspace between the panes is constant between the two constructions. In other words, consider a triple pane with two 1/4" airspaces and a dual pane with a single 1/2" airspace...both using 1/8" glass...the STC will be identical if the IGU's are the same dimensions.

What I suspect you saw on HGTV was a product called Heat Mirror. The Heat Mirror folks have a suspended plastic sheet between two lites in an IGU and they claim that this suspended sheet of plastic makes their window superior to any other window on the market in just about everyway you can imagine, up to and including performing minor surgeries if needed. Are the claims true? Yes and no, the energy perfomance numbers for heat mirror are amazing, and the product does have some very nice sound perfomance numbers as well. But, the Heat Mirror product specifically recommended for sound attenuation also has a huge gap between the lites and the suspended film. When folks talk about how good this product is at blocking sound (I have also seen it discussed on HGTV, but I don't know if it was the same show or not that you sae, of course), they love to talk about that suspended piece of plastic. What they never mention (at least I have not seen) is that the real value is the width of the airspace combined with the make up of the unit.

Using one thicker (3/16") and one thinner (1/16") lite in an IG construction will also help deaden sound because each lite is "transparent" to a different frequency and each lite will then attenuate the frequency that the other lite "passed".

What a company like Soundproof Windows will do is build what is essentially a laminated glass storm window and install it over your existing window.
I have a few issues with some of the things they say on their website concerning energy performance improvements that they claim, and the amount of sound that they claim they will block. I also think that they charge a premium for their product, but if done correctly, then it will work quite well.

If you decide on installing a new window, then remember that, as always, the quality of the construction and especially the installation cannot be overstated! Based on the size of the unit, fixed (not an operator)is a definite advantage when attempting to stop noise from coming in your house.

A fixed, non-operable, window will often show significant improvement over an operating window which is one reason why the soundproof folks do so well. They install a fixed "storm" and make sure that the original window is also tight...it does work.

A few numbers for comparison (glass only, not a specific window construction):

A 1/4" monolithic lite has an STC of 31.
A 1/4" laminated lite has an STC of 35.
A 1/2" (overall width - airspace width is 1/4") IGU has an STC of 28, lower than a single sheet of 1/4" glass. Surprised? If anyone is curious, I can explain the principle behind that one.

Increase the airspace in the IGU to 3/8" from 1/4" and the STC increases to 31, or the same as a monolithic 1/4" lite!
One disclaimer, generally speaking, in the real world few monolithic windows are made using 1/4" glass.

Replace one of the 1/8" monolithic lites in the IGU mentioned above with a 1/4" laminate, and the STC jumps to 35, which happens to be the same as the monolithic laminate alone. If anyone is wondering, it is that pesky, narrow airspace of 1/4" that is the problem. Again, I can talk more in depth about that if anyone is interested.

In the same laminated glass / IGU make up, that I just mentioned, if we increase the airspace to 1/2", then we jump the STC to 39.

And, finally, if we want to get really serious, increase the airspace to 4" and use laminated glass on both sides of the airspace and we get an STC of 53, or airport-style sound deadening. Now before anyone gets overly excited, the cost of such a construction is rather significant! ;-)

Hope this made at least some sense! "

F.S.